Electrical condenser



, 1,6 2, 52 Jun? .14 1927' J. M. STEWART 3 3 ELECTRICAL CONDENSER Filed Nov. 4. 1924 2 Sheets-Sheet 1 FIG. 1

l 632,352 June 1.4"1927 .1. M. STEWART ELECTRICAL CONDENSER Filed Nov. 4. 1924 2 Sheets-Sheet 2 FIGA I nvenor John M.Stewarb Patented June 14, 17927.

UNITED STATES 1,632,352 PATENT OFFICE.

ELECTRICAL coNnENsnn.

application mea November 4, 1924. 'serial No. 747,87?.

My invention relates generally to electrical condensers and more particularly. to variable air condensers used in radio circuits.

An object of the invention is to provide a condenser having dual control through v a single knob.

Another object of the invention'is to pro vide a condenser particularly adaptable for aircraft sets.

A further object is to provide acondenser permitting the greatest economy in panel board `space without complicating the mov-I able plate control.

A still further object is to provide a condenser which reduces the cost of manufacture to a minimum without sacrificing any of the advantages of dualvcontrol. i

With these and otherV objects in view, the invention consists in the construction, combination, and arrangement of parts as will be hereinafter described.

Reference is to be had to the accompanying drawings forming part of this specification, in which like reference characters indica'te corresponding parts throughout the several views, and in which Figure 1 is a sectional View showing my dual control means.

Figure 2 is a perspective view partly broken away. j

Figure 3 is a fragmentary perspective v iew of the plate used therein, and

Figure 4 is a sectional view of a modification particularly adapted for aircraft sets.

Referring more particularly to the drawings, 5 indlcatesa panel board to which the condenser top 6 is attached by spacers 7. The usual stationary plate assembly 8 and movable plate assenbly 9 are contained within the condenser. The movable plates are secured to the` spindle 10 which is pro' vided with an enlarged recessed head 11 and a guideway 12 extending therefrom. A plate 15 having integral upstanding arms 16 and laterally extending ears 17, the purpose of which will belater explained, is secured to a compound gear 23 in any suitablel man-y ner. This plate, which maybe stamped from a single piece of material, is also provided with a 180 degree slot 19permitting movement thereof about a stud 20 passin through an opening 21 in the top 6 an clamped thereto by any suitable means, such as a screw 22. The brass compound gear 23, that is, a gear having an extended toothed periphery 2 4- and an interiorly beveled hub i portion 25, is secured to the head 11 sweatmg, or by a key 18, as shown, It is to be understood'that the bevel may be cont str ucted for either friction, milled or toothed drive. The stud 20 carries an insulatedl gear 26 having an elongated hub which supports a metal, preferably brass, gear 27 having a beveled contacting surface constructed simiwlarlyto that of hub 25. rllhe gear 26 engages Withthe toothed portionof gear 23. A shaft 28 passing through the condenser dial 29 and separated therefrom'by the bearing 30 has removably vsecured thereon at its interior end a double beveled gear 31 the surfaces of which are constructed similarly to the surfaces of 25 and 27 with which it respectively engages. The gear may be made in one piece as in Figure l or two pieces as in Fig. 4.

The interior end of the shaft is reduced forming a guidepin 1/1 which slides in the guideway 12 keeping it true assuring positive engage-ment of the gears. A spring 13 In its normal position, or that shown in Figure 1, the condenser is ready for'fine adjustment, main adjustment being obtained by pressing inthe knob disengaging gear 31 from 27 and engaging it with gearl25. In operation fine'adjustment is a more lengthy manipulation than vmain adjustment which is the reason for having the condenser in positionfor such adjustment. To prevent the end of the slot 19 coming into abrupt contact with theY stud 20, which might cause injury to the delicate construction of a con-- denser, 1 provide a buffer or brake 33 on the top 6 in such position that the ears17 -will contact therewith as the platel approaches j the limits o-f its travel in either direction.

The dial 29 is provided' with the usualdegree markings, as may be seen in Figure 2 and an indicating mark on the'panel 5 co-acts therewith in adjustment of the movable platelassembly,l and, in order to reduce to a minimum the .capacity effect of the body, the

vdial is electrically groundedto the panel ring away from the enlarged head 11 of the spindle 10 by the spring contacting with the outer wall of recess 36, and when in position for line adjustment by contacting with the inner wall of the recess 37,

' It is understood that the above description and accompanying drawings disclose only the preferred improvement of my invention and that various mino-r changes in details of construction, proportion, and arrangement of parts may be resorted to within the scope of the appended claims and Without sacrificing any of the advantages of my invention.

Having fully described my invention, what I desire to secure by Letters Patent 1s:-

1. A controll mechanism including a support, a shaft journaled in the support, a gear housingaxed to the shaft, a train of gears within the housing for impartin i motion thereto, means for rotating the sha t consistingof a spindle journaled in the housing and movable parallel with the shaft, means upon the end of the spindle engageable di rectly with the end of the shaft for direct rotation thereof by the spindle in its inward position and engageable with the train v.of

gears for the indirect rotation of the shaft by the spindle in its outward position, the

means consistingof a double bevel gear.

2.` A control mechanism including a support, a shaft journaled in the support, a gear housing aiixed to the shaft, a train of gears' within the housing for imparting motion thereto, means for rotating thev shaft consisting of a spindle journaled in the housing and movable parallel with -the shaft, means upon the' end of the spindle engageable directly with the end of the shaft for direct rotation thereof by the spindle in itsv inward position and engageable with the train of gears for the indirect rotation of the shaft by the spindle in its outward position and means for maintaining the means upon the end of the spindle in pressure engagement with the end of the shaft at the inner position of the spindle.

t 3. A control mechanism including a support, a shaft journaled in the support, a`

gear housing aliixed to the shaft, a train of gears within the housing for imparting motion thereto, means for rotating the shaft,

engagement with one of the train of gears in the outward position of the spindle.

JOHN M. STEWART. 

